Hydrocarbon oil treatment



i I crude, such as onefrom the Gulf'coast area, will Patented Jan. 1, 1936 UNITED s'r'Aras PATENT oF-ncr.

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Edwin B..-.Birkhlmer, 1'hlladelphia,1a., alsignor to The Atlantic Refining Company, Philadelphia, Pm, a corporation of Pennsylvania No Drawing. Application March 25,193 i Serial Nacsaus i cinims. (c1. lac- 13 p v The present invention relates to the art of mineral oil refining, and has particular reference to the separation of crude petroleum orpetroleum products into fractions of difl'erentchemicai com- 5 position while of approximatelythesame distillation range.

substantial viscosity; are separated into various fractions by means of' fractional extraction with an aliphatic-aromatic ketone, and more partic-' ularly acetophenone.

It is recognized in the artthatmineral nus, suchaspetroleum, comprise essentially amixture j of hydrocarbons of various groups orhomologous ,1 series of compoundsQsuchforexamplaas parof the general formulaCnHznn, olefines of the general formulaCnHzn, hydroaromatics and polymethylenes of the same empirical formula,

and various other series of "compounds of chain and/or ring structures in which thehydrogen to carbon ratio is lessithan in the foregoing series. A large number of individual compoundsof each series and of differing boiling points are present in petroleum.

The various types 'of crude petroleum, which aregenerally classified intothree groups, namely,

c parafllnic, base, naphthenic or asphaltic base,.and

3 mixed base, contain thevarious series of hydrocarbons mentioned heretofore; indifferent proportions. For example, in the paraifin base crude oils, such as those obtained from the oil fields of k Pennsylvania, therefis a relatively highlp'roportion of hydrocarbonshaving a, chain structure a and a high hydrogen to carbon ratio, whereas in naphthenic or asphaltic base crude oils, there i, is a relativelylarge proportion of hydrocarbons having ring, structures and a low hydrogen to carbon ratio. Mix

and having a-viscosity at E, of about 0.878, whereas an oil of corre- 89 1 1 8 vi ty produced from a. naphthenic indicates the degree of parafilnicity or p p in accordancewith my invention,'crude petroleum'or petroleum products, particularly oilsof fractions for some of 400 seconds 'Saybolt universal at It, will show a'specificgravity'" show a specific gravity of about 0.933 at 60F.

The'relationship between the viscosity and gravity naphthenicity of the oil, and such relationship may be expressed by the viscosity-gravity constant as s hereinafter described.

, Ii agiven crude petroleum be distilled into successive fractions and the specific gravities and visfcosities of the several. viscous fractions be determined, it will be found that they conform to the 10 general relationshipexpressed by the IOI'lI-illlD- in which is the specific gravity at 60 in, v"

and .V' are respectively Saybolt universal viscosities at'l00 F. and 210 F., and a is a Iconstant known "as the viscosity-gravity constant. 20 Viscous fractions from each of the different types of crude have different viscosity-gravity constants. While, in general, viscous fractions from a single crude have substantially'the same viscosity-gravity constant, such constant is lower 25 for fractions of the parafilnic crudes than is the constant for fractions of the naphthenic crudes. An articleentitled The viscosity-gravity constant of petroleum lubricating oils by J. B. Hill and H. B. Coats, which will be found involume 20, page 641' et seq., Industrial and Engineering Chemistry for June, 1928, explains the determination of such constant for several typical oils.

' 'I'hejviscosity-gravity constantis, therefore, an index of the paraifinicity or naphthenicityof 36 viscous oils, since when a given crude is distilled, the fractions thereof collected, and the specific gravity and the viscosity of each of the viscous fractions determined, such specific gravitiesand the -formula,- andxthe 4 viscositi'es substituted in viscosity-gravity constants of the fractions'cal- .culated, it will be found that such constants are substantially the same.

The viscosity-gravity constants of the viscous of the typical crudes are as 5 follows: y

Milltown (Pennsylvania) 0.8067 Burbank, (Mid-Continent)... 0.836! Guadalupe (Gilli C0851") 0.8635 50 MlrandoiGulf Coast) "0.9025

- while the above figures indicate the viscositygravitycon'stants of specific oils from several types of crudes,it is to be understood that for. any particular type of crude such constant may 6 .palachian crudes, from crudes be within a range between values above and below the constant of the typical crude given. For

about .855, whereas the viscous fractions resultingfrom the distillation of Pennsylvania type crudes range from about .805 to about .828, and

in most instances, are below .820. Oils are increasingly parafiinic as their viscosity-gravity constants decrease.

My invention is based-upon the discovery that oils containing both the paraflinic series of by" drocarbons and the various naphthenic series may be fractionally extracted with acetophenone. The various series of hydrocarbons pos'-'- sess a differential solubility in such solvent, the naphthenic hydrocarbons being much more soluble therein than the paraiiinic hydrocarbons. By means of extraction with such solvent, it is therefore possible to eifect a partial separation of the naphthenic hydrocarbonsfrom the parafllnic, and to obtain from an oil containing both classes of hydrocarbons, an oil which is much more paraflinic than the original oil and one which is much more naphthenic. By my invention, for example, it is possible to produce an oil of the quality normally obtained from Apof v the mixed base type from the Mid-Continent area, and conversely, to obtain oils from mixed base crudes such as are normally obtained from the naphthenic oils of the Gulf coast area. In general, from oils from any source there may be obtained by my process, oils which are respectively more 1 paraffinic and more naphthenic than the oils normally. obtained from such source by distillation. 1 In accordance with my invention, I first mix the oil tojbe treated with a suitable proportion ,Of. the solvent at a temperature such that complete solution is eiIected and a homogeneous liquid obtained. I then cool the mixture to a temperature at-which separation of the liquid into a two-layersystem will take place. The upper layer will contain a relatively small amount of the solvent dissolved in the parafiinic portion of the oil while the lower layer will contain the more naphthenic portion ofthe oil dissolved in the solvent. Or, I may agitate the mixture of solvent and oil at temperatures at which the liquids are only partially miscible, and thereby effect solution of the naphthenic portion of the oil in the solvent. In eitherof the above pro-' cedures I may take advantage of the principles of counter-current extraction.

After the extraction proper, I effect separation ofthe two layers which form, by any suitable I procedure, as for example, by decantation. I-

then remove from each of the separated layers, the portion of solvent which each contains by suitable procedure, such as by vacuum distillation, thereby to obtain. two oils of similar distillationranges but of different chemical compositions and diflerent physical characteristics.

Before removing the solvent from the upper and more parafllnic layer, I may add a further quantity of solvent and repeat the extraction, thereby to remove additional naphthenic constituents from said layer. The extraction step may be repeated any desired number of times, each repetition producing an oil of higher paraflinicity as evidenced -by its lower viscositygravity constant. 7

, Where substantial quantities of waxy hydrothe original oil.

carbons belonging to the true paramn series (Celina) are present, such hydrocarbons remain in the upper or more paraifinic layer and may cause such layer to be solid or semi-solid. Such-layer may be separated into solid and 5 liquid hydrocarbons by any of the well-known dewaxing processes'such as by cold-settling or by centrifuging. In many instances it may be advantageous to dewax the oil prior to extraction. However, it is to be understood that in accord- 10 ance with my invention, dewaxing may be effected either prior or subsequent to extraction. My invention will be further understood from ,the following specific example:

' slightly above the temperature of complete mis- 20 cibility, which. was approximately 42 0.. The homogeneous liquid which resulted was cooled with agitation to 20 0., and allowed to settle, whereupon a two layer system formed. After separation; the layers were each freed of sol- 25 vent by vacuum distillation. The undissolved oil fraction comprising 57.0% of the stock had a viscosity of 126 seconds Saybolt universal at 210 F., a specific gravity of 0.895, and a viscosity-gravity constant of 0.810. The dissolved oil fraction comprising 43.0% of the stock had a viscosity of 204 seconds Saybolt universal at gravity of 0.948 and a viscosity-gravity constant of 0.872.

From the above example it will be noted that 86 by extraction of an oil with acetophenone, there may be obtained oil fractions which are respectively more parafilnic and more naphthenlc than By repetition of the extraction process upon the undissolved fraction, oils of even 40 greater paraffinicity will result.

My process is practically independent of the particular nature or source of the crude oil or oil fraction to be extracted. There may be produced by my process oil products of desired char- 45 acteristics from oils which by distillation will not produce such products. I

Hereinabove, mixtures 'of solvents have been referred to. It is to be understood that in such mixtures the constituents will not react with'one 50 another nor with the oil upon which they are to be used, and that such mixtures will contain substantial amounts of acetophenone.

For brevity, herein and in the appended claims acetdphendne is employed in a generic sense to 55 include acetophenone or equivalent aliphatic aromatic ketones which are capable of selectively separating an oil into fractions respectively richer in paraflinic and naphthenic hydrocarbons, or mixture of solvents containing one or more of 60 the said aliphatic-aromatic ketones.

Also, when herein and in the appended claims, oil is specifically referred to as being viscous,

' it is to be understood that the oil is of substantial oil containing paraflinic and naphthenic hydrocarbons. heating the mixture to such temperature as to eflect solution, cooling the solution to form a two-layer system, and separating the upper layer from the lower layer.

3. In the art of refining mineral oils, the process which comprises adding acetophenone to an oil containing paraflinic and naphthenic hydrocarbons, heating the mixture to such temperature as to eiiect solution, cooling the solution to form a two layer system. removing the lower layer, and similarly retreating the upper layer with acetophenone.

4. In the art of refining mineral oils, the process which comprises bringing a mineral oil containing parafflnic and naphthenic hydrocarbons into contact with acetophenone thereby to effect solution 01 a portion richerv in naphthenic hydrocarbons in the solvent, separating the solution so formed from the remainder of the oil, and removing the acetophenone from both portionsoi. the oil, thereby to obtain fractions of the oil respectively richer in parafllnic and naphthenic hydrocarbons.

5. The process for separating mineral oils containing paraflinic and naphthenic hydrocarbons into fractions which comprises bringing the oil into contact with acetophenone thereby to eiiect solution of a portion of the oil richer in naphthenic hydrocarbons in the acetophenone, separating the solution so formed from the remainder oi the oil, and distilling the acetophenone from both of the portions of the oil, thereby to obtain I fractions of the oil respectively riched in parafllnic and naphthenic hydrocarbons.

6. In the art of refining mineral oils, the process which comprises bringing a mineral oil containing paraillnic and naphthenic hydrocarbons into contact with acetophenone thereby to eflect solution of a portion richer in naphthenic hydrocarbons in the acetophenone, separating the so- 'lution so formed from the remainder of the oil.

and retreating the oil remaining with additional amounts of acetophenone.

'l. The method of producing parafllnic lubricating oil from mixed base crude which comprises distilling the crude and bringing a portion thereof into contact with acetophenone, thereby partially dissolving the oil, separating the acetophenone solution of oil so treated, and removing the acetophenone from the treated oil.

8. In the art of refining mineral lubricating oil containing parafllnic and naphthenic hydrocarbons, the step of fractionally extracting the oil with acetophenone, to eflect a separation of fractions respectively richer in parafllnic and naphthenic compounds.

9. The process of treating a viscous fraction of a crude oil 01 one type containing paramnic and naphthenic hydrocarbons to procure a fraction having the quality of a corresponding fraction of a crude oil oi difle'rent type having a greater content of paramnic hydrocarbons, which comprises extracting the viscous fraction with acetophenone and separating the oil so treated into portions respectively richer in parafllnic and naphthenic hydrocarbons. 5

10. The process of treating a viscous fraction of a mixed base crude oil to procure a fraction having the quality of a corresponding fraction of a paraflinic base crude, which comprises extracting the viscous fraction with acetophenone, i0 and separating the oil so treated into portions re-' spectively richer in parafllnic and naphthenic compounds.

11. In the art of refining mineral oils, the process which comprises adding acetophenone to a ll viscous oil liquid at ordinary temperatures containing parafllnic and naphthenic hydrocarbons, heating the mixture to a temperature sumcient to eiiect solution, cooling the solution to a temperature sufllcient to form two layers respec- U tively richer in naphthenic hydrocarbons and parafllnic hydrocarbons other than wax, and separating the upper layer richer in paramnic hydrocarbons from the lower layer richerin naphthenic hydrocarbons.

12. In the art of refining mineral oils, the process which comprises bringing acetophenone into intimate contact with a viscous hydrocarbon oil of a quality other than that or a Pennsylvania type viscous oil, and containing parafllnic and I0 naphthenic components, thereby to dissolve from the oil substantial amounts oi. its naphthenic components, thereafter removing the solvent and oil dissolved therein from that portion of the oil which remains undissolved, thereby to produce I an oil such as is normally obtained from Pennsylvania type crude by distillation.

13.Tiie" process of decreasing the viscositygravityjhonstant of a viscous mineral oil which comprises extracting the oil with acetophenone.

14. Theprocess of decreasing the viscositygravity constant or a viscous mineral oil at least 0.015 which comprises extracting the oil with acetophenone. f g g 15. The process K I treating a viscous mineral 48 oil of viscosity-gravi' constant 'between substantially 0.835 and 0.875 to reduce the viscositygravity constant by at least 0.015, which comprises ifractionally extracting said viscous oil with acetophenone.

16. The process of treating a viscous mineral oil of viscosity-gravity constant higher than 0.835 to produce an oil having a viscosity-gravity constant less than 0.815 which comprises fractionally extracting said viscous oil with acetophenone.

17. The process oftreating a viscous mineral oil of viscosity-gravity constant higher than 0.835 to produce an oil having a viscosity-gravity constant of less than 0.828 which comprises fractionally extracting said viscous oil with aceto- 00 phenone.

EDWIN R. BIRKHIMER. 

